Alarm system and signalling apparatus therefor



July 17, 1956 A. F. SPERRY 2,754,793

ALARM SYSTEM AND SIGNALLING APPARATUS THEREFOR Filed Oct. 1, 1954 2Sheets-Sheet l 71 o ffilN VEN TOR.

July 17, 1956 A. F. SPE-RRY 2,754,793

ALARM SYSTEM AND SIGNALLING APPARATUS THEREFOR Filed Oct. 1, 1954 2Sheets-Sheet 2 INVENTOR.

)(efa w United States Patent ALARM SYSTEM AND SIGNALLING APPARATUSTHEREFOR Albert F. Sperry, Chicago, Ill., assignor to Panellit, Inc.,Skokie, 111., a corporation of Illinois Application October 1, 1954,Serial No. 459,692 9 Claims. (Cl. 116-4) This invention relates to fluidfor supervising situations wherein the system gives both audible andvisual signals indicating the occurrence of an abnormal condition andidentifying the supervised apparatus or area. The condition to besupervised may be evidenced by temperature or pressure, liquid level,rate of flow, or innumerable other conditions which must besuperintended for reliable indication of an abnormal condition.

The invention comprises broadly a fluid operated system combined withinstruments responsive to changes in pressure in the system. Upon theactuation of the fluid system by the occurrence of an abnormal conditionin the apparatus or area being supervised, warning signals, both visualand audible, are brought into operation. While the audible signal may besilenced, the visual signal reoperated alarm systems mains operativeuntil normal conditions are again established in that which is beingsupervised.

Alarm systems commonly comprise a plurality of individual alarm units onan instrument panel board, each unit having a visual indicator whichresponds to changes in the condition supervised. When an abnormalcondition occurs, the individual alarm unit connected to the apparatusor area supervised responds to the condition and visually signals theoccurrence of such condition. In addition, the alarm unit causes anaudible alarm to operate in order to draw attention to the visualsignal. Complications arise, however, in the use of such systems inareas where the atmosphere is likely to be filled with gas or dust, orwhere other hazardous conditions exist. In such locations, electricalsystems may be prohibited, or only conditionally allowed. Even under thelatter condition, the requirement of suitably protecting againstaccident, fire and explosion may make the use of electrical systemsunfeasible. The design of such electrical protection means as metallicenclosures and hermetic seals makes the equipment large, cumbersome andinflexible, besides being expensive. Therefore, under such conditions,the use of a fluid operated system becomes both practical andeconomical.

In an alarm system, upon actuation of an alarm unit, it is desirable tohave the audible alarm continue to signal until notice has been taken ofthe visual signal. Thereafter, it is best to silence the audible alarmwhile leaving a visual indicator showing on the alarm unit. Thus, thereis no annoyance from a continually sounding alarm While the abnormalcondition is being corrected. For simplicity of construction, it furtheris desirable to have a common audible alarm device which becomesactuated whenever any one of a group of alarm units indicates theoccurrence of an abnormal condition. Silencing of the actuated commonaudible alarm should not, however, affect the other alarm units, whethersignalling or in normal operating position, in any manner. The visualindicators of other actuated alarm units should remain in evidence whilethe audible alarm is silenced and prepared to sound attention to anynewly activated alarm unit.

In carrying out this invention, one of the objects is to provide anextremely compact instrument panel which serves to supervise a pluralityof apparatuses or areas, gives visual warning of an abnormal condition,and, in addition, sounds an audible alarm to draw attention to theinstrument panel.

An important object of this invention is to supply an alarm unit whichvisually indicates the existence of an abnormal condition whilesimultaneously sounding an audible alarm, and including means wherebythe audible alarm may be silenced while leaving a visual indicator onthe instrument panel to show where the fault exists.

A further object of this invention is to provide an alarm system whichwill permit restoration of an activated alarm unit to normal operatingposition only after correction of the abnormal condition which causedthe alarm.

Another object of this invention is to provide a highly sensitive,reliable and accurate, and at the same time economical and simple fluidoperated alarm system which may be used in hazardous areas where the useof electrical systems is prohibited or highly unsafe. The fluid alarmsystem used should further provide the full equivalent protection of anelectrical alarm system.

Still another object is to provide an alarm unit which is readilyadaptable to either pneumatic or hydraulic pressure activation, andwhich is applicable to all alarm purposes.

It is also an important feature of this invention to provide an alarmunit which visually distinguishes between acknowledged andunacknowledged signals, having an audible signal to attract theattention of an attendant to any existing unacknowledged signal.

Since many areas or apparatuses may be supervised on one instrumentpanel, it is accordingly another object of this invention to provide anentire alarm system which permits resetting of the individual alarmunits for the corrected supervised areas or apparatus while notexinguishing other alarms which also may-be existing.

The foregoing and other objects of the invention are fully met by analarm system having individual alarm units forming a series ofinstruments, with a small spring biased and rotatable alarm indicatordisc in each unit; A pressure actuated bellows is further provided ineach unit, acting to release the disc upon the occurrence of an abnormalcondition, thus exposing the disc over part of its area. Between thedisc and bellows a simple linkage is provided, comprising a fixed shafthaving two movable fingers attached thereto, and a disc actuating shaftwith a segment cooperating with the two fingers. A third finger,attached to one of the other fingers, actuates an audible alarm which issilenced by a manually operated acknowledgment toggle switch.Acknowledgment of the alarm also releases the disc, enabling it toexpose another portion of its area. Reset mechanism on the discactuating shaft, and mechanically actuated by a reset toggle switch,returns the disc to its normal position upon correction of the abnormalcondition.

Other objects will become apparent from the follow ing detaileddescription, it being understood that the alarm system may be applied ina variety of modifications without departing from the scope of theinvention.

In the drawings:

Figure l is a fragmentary perspective view of an instrument panelcontaining a plurality of individual alarm units;

Figure 2 is a sectional view of an individual alarm unit and showing thealarm indicator disc in normal operating position, and further showingthe field sensing valve and reset toggle switches;

Figure 3 is an enlarged sectional view of the alarm acknowledge toggles;

Figure 4 is a sectional view similar to Figure 2 with the alarmindicator disc signalling the existence of an abnormal condition;

Figure 5 is a'view similar to Figures 2 and 4, and showing the alarmindicator disc in alarm-acknowledged position; and

Figure 6 in Figure 2.

Referring to Figures 1 and 2, the invention includes an alarm instrumentpanel 11 in which individual annunciator alarm windows 12 are placed foreach alarm unit 13 housed within the panel. Each alarm unit 13 isinterconnected with its own normally open field valve 14 by itscorresponding pressure line 15. Each field valve 14 is interconnected toa pressure header source 16, and under normal operating conditions valve14 remains open. The occurrence of an abnormal field condition causesvalve 14 to close whereupon a signal is given in alarm unit 13. Valve 14may be any of the usual types of valves which are used to respond toabnormal conditions. For example, it may be a float valve or the likeoperated by high or low liquid levels.

The individual alarm units 13 are each provided with a housing 17 whichis attached to panel 11 by suitable means such as bolting. At the rearof housing 17 an aperture 18 is provided, permitting pressure line 15 tolead into housing 17 where it ends in bellows 19. A bracket 20,connected to the housing 17 by rivet 21, provides a mounting means forbellows 19. As best shown in Figure 2, bellows 19 when subject toatmospheric pressure remains in a contracted position. When field valve14 senses an abnormal condition, however, it closes, and pressure isdirected to bellows 19 which becomes extended.

Referring to Figures 2 and 6, housing 17 contains a principal operatingshaft 23 having sleeve 22 and alarm disc 24 non-rotatably securedthereto. Under normal operating conditions disc 24 is maintainedentirely within panel 11. Bearings 25 and 26, secured to the sides ofhousing 17, rotatably support shaft 23. A drum 27, also fixed to shaft23, is provided for reset cable 23 to wind upon as shaft 23 is rotated.Spring 29 furnishes a turning movement to the shaft 23, tending torotate shaft 23 counterclockwise as viewed in Figure 2.

Sleeve 22 is recessed at 30 to hold. detent 31 therein by means of pin32, thus providing a stop means for shaft 23. Spring 33 supplies aslight outwardly directed bias to detent 31 to assure that it will beengaged by stops as shaft 23 rotates counterclockwise, as will beexplained more fully hereinafter. As shaft 23 is returned to itsstarting position, however, spring 33 permits detent 31 to be urged towithin recess 30.

A fixed shaft 34, supported at its ends by standard 35 and support 36,is provided within the alarm unit 13, supplying a mounting means forStops which control the movement of shaft 23 and disc 24. Bellcrank 37,rotatively mounted upon shaft 34, is pivotally connected at the outerend of one arm 38 to lifting rod 39 carried by bellows 19. The otherbellcrank arm 40 carries an escapement lever 41. Upon expansion ofbellows 19, rod 39 moves upwardly, rocking bellcrank 37, therebyslipping escapement lever 41 from engagement with detent 31. The releaseof detent 31 from engagement with lever 41 permits spring 29 to rotateshaft 23 counterclockwise.

As seen in Figure 4, a second escapement lever 42, also rotativelymounted upon shaft 34 and adapted to engage detent 31, provides a meansto stop the rotation of shaft 23 after it has travelled approximatelyninety degrees. Since spring 29 continuously tends to rotate shaft 23,lever 42 is rotated slightly by detent 31 until its end 43 engages slide44 mounted in housing 17, thereby stopping both shaft 23 and lever 42.Spring 45, attached to post 46 and at its other end to lever end 43,provides a means to return lever end43 to its original position. In suchposition, end 43 engages the open is a sectional view taken along lines66 bleeder end 47 of pressure duct 48. The position of disc 24 shown inFigure 4 indicates an alarm position which is the result of theoccurrence of an abnormal condition in the field. In this position, thatportion 24a of disc 24 which is showing may be painted red.

An audible alarm also is provided, drawing attention to the instrumentpanel '11 whenever an abnormal condition occurs. Constant pressure issupplied through line 49 to a normally closed needle valve 50. As shownin Figure 1, branch header 51 and orifice 52 direct pressure to take-offlines 48 in the individual alarm units. A drop in pressure in header 51causes normally expanded bellows 53 to collapse, moving rod 54, andopening needle valve 50. In its normal operating position, lever end 43also acts as a bleeder valve, closing the open bleeder end 47 of duct48. In the position shown in Figure 4, however, lever end 43 is movedsufficiently to permit bleeding off of pressure in line 48 and header51, thereby collapsing bellows 53 to open'needle valve 50. Opening ofvalve 50 permits pressure from line 49 to sound whistle alarm 55.

To effect acknowledgment of both the visual and audible alarms, theacknowledgment toggle 56 is flipped upwardly, thereby movingacknowledgment arm 57 and lever 58 downwardly. Lever 58, pivotallyconnected to arm 61) of acknowledgment bellcrank 59, rocks bellcrank arm61 to move slide 44 held in guide 62. Bellcrank 59 is pivotally mountedat 63 to the rear of alarm housing 17. As slide 44 moves outwardly, itslips from contact with end 43 of lever 42, permitting detent 31 to ridefree from lever 42 as spring 29 rotates shaft 23 and disc 24approximately degrees to the position shown in Figure 5. Inacknowledgment position, that portion 24b of disc 24 which is showingmay be of some other color, such as blue, in order to distinguish fromthe unacknowledged alarm position. Another spring 64 aids in returningslide 44 to its original position.

As detent 31 rides free from lever 42, spring 45 returns lever end 43 toits original position in contact with the bleeder end 47 of line 48.With normal pressure restored in header 51, bellows 53 expands, movingrod 54 to close needle valve 50. The closing of valve 50, in turn cutsoff the flow of air to whistle 55, thereby silencing the audible alarm.

After the alarm has been acknowledged and the abnormal field conditionhas been corrected, reset of alarm unit 13 to its normal operatingposition is accomplished by moving reset toggle 65 upwardly, therebymoving reset arm 66 down and pulling upon cable 28. This counteractsspring 29 to rotate shaft 23 clockwise and back to its normal position.

It is evident that as long as a normal condition exists in the area orapparatus being supervised, bellows 19 remains collapsed. This featuresafeguards against nonsignaling units being actuated by operation oftheir corresponding acknowledgment toggle switches 56. With bellows 19collapsed, lever 41 is retained in engagement with detent 31, therebystopping rotation of shaft 23.

A second safety operational characteristic frees the alarm units fromthe hazard of losing a signalling alarm. As a consequence of theoccurrence of an abnormal field condition, line 15 experiences apressure increase which causes bellows 19 to expand. Bellows 19 remainsexpanded as long as the abnormal condition exists, thereby preventingescapement lever 41 from engaging detent 31. Thus, if reset toggle 65 isflipped on an unacknowledged signalling alarm unit 13, the expandedbellows 19 causes lever 41 to slip from the detent 31, and shaft 23rotates until stopped by lever 42 engaging detent 31. In this position,disc portion 24a reappears in panel 11, as shown in Figure 4, andcontinues to signal that an abnormal condition exists.

As shown in Figures 1, 2, and 3, a gang acknowledgment toggle 67 and agang reset toggle 68 also are provided. When gang acknowledgment toggle67 is flipped up, gang acknowledgement arm 69 moves downwardly causinggang crossbar 70 also to move down. The downward movement of crossbar70' forces the individual acknowledgment arms 57 to move downwardly,and, in turn, acknowledges the individual alarm units which havesignaled the occurrence of an abnormal field condition. Non-signallingunits keep their normal operating position. since bellows 19 remainsunextended, retaining lever 41 in engagement with detent 31 and stoppingshaft 23 from rotating.

Gang reset toggle 68 resets all signalling alarm units which havepreviously been acknowledged and whose field condition is again normal.Raising of gang reset toggle 68 causes gang reset crossbar 71 to movedown, forcing the individual reset arms 66 also to move down. Thiscounteracts the individual springs 29, resetting those alarm units 13that have previously been acknowledged. If an alarm unit has not beenacknowledged, it will continue to signal the existence of an abnormalcondition as long as such condition continues, since its bellows 19remains extended as long as greater than atmospheric pressure isdirected into the alarm unit 13. Under such a condition, escapement 41is prevented from engaging detent 31, permitting spring 29 to rotateshaft 23 until detent 31 abuts escapement lever 42 and disc portion 24aagain is showing on the instrument panel.

Although the acknowledgment and reset of the alarm units 13 have beenshown at the instrument panel 11, this invention is not limited to suchstructure. The alarm units 13 are adaptable to solenoid actuation ofslide 44 and to the provision of either a mechanical or electricalrewind construction for shaft 23.

The operation of the alarm system thus described is as follows:

As normally open'field valve 14 senses an abnormal condition, it closesand pressure is directed to alarm unit 13 whose bellows 19 immediatelybecomes expanded. Expansion of bellows 19 turns bellcrank 37sufliciently to allow escapement 41 to slip from engagement with detent31. This brings about the indicator alarm position shown in Figure 4,wherein shaft 23 has been rotated about ninety degrees by spring 29, anda portion 24a of disc 24 visually indicates the existence of theabnormal condition.

Rotation of shaft 23 and disc 24 in the unacknowledged signalling alarmunit 13 is stopped by detent 31 engaging escapement lever 42, rotatingescapement lever 42 slightly until the lever end 43 abuts slide 44. Themovement of lever end 43 from the open bleeder end 47 of duct 48 causesthe pressure to drop in header 51, collapsing bellows 53. As bellows 53collapses, it moves rod 54 to open needle valve 50, permitting air fromline 49 to actuate whistle 55.

To acknowledge the alarm, either acknowledgment toggle 56 or gangacknowledgment toggle 67 is flipped upwardly, pulling slide 44 fromengagement with lever end 43, and allowing shaft 23 to rotate to theposition shown in Figure 5. In the meantime, spring 45 urges lever end43 back against the bleeder end 47 of duct 48, returning the pressure inheader 51 to normal, and thus expanding bellows 53. Expansion of bellows53 closes valve 50, shutting off air to whistle 55, and silencing theaudible alarm.

After the abnormal condition has been corrected, either reset toggle 65or gang reset toggle 68 is flipped upwardly, pulling upon cable 28 androtating shaft 23 clockwise to normal position, as shown in Figure 2. Innormal position, detent 31 and escapement 41 again abut one another.

By placing the toggle switches at a convenient point near the alarmwindows 12, the attendant, when called by the audible alarm whistle 55,is brought in front of the instrument panel 11 and his attention shouldbe caught by the visual alarm disc 24 of the actuated alarm unit 13. Ifthe attendant does not notice the visual sign, however, the indicatordisc 24 persists as long as the abnormal condition survives and thealarm unit has not been reset.

With many alarm units at one instrument panel, it may happen thatsounding of the alarm whistle 55 is caused by one alarm unit 13 whilethe condition in another supervised area or apparatus which previouslyactuated another unit 13 at an earlier time has not been brought back tonormal. Then, visual discs 24 belonging to both units appear in theirrespective windows 12. However, the attendant still is able to identifythe newly actuated alarm by noticing the particular color in each window12 and the position of the respective discs 24.

To protect the discs 24, and to prevent the entrance of dirt into theindividual units 13 by way of the windows 12, a clear Lucite shield 72is provided on panel 11.

While the structure described described forms a satisfactory alarmsystem, it is to be understood that other forms may be utilized, andthat the embodiment herein enumerated is for the purpose of illustrationonly and not intended to limit and define the invention. One such formsuggests itself, namely, the alarm units are adaptable to respond toelectrical sensing devices, or the units may respond to pressure systemswherein there is a pressure drop upon the occurrence of an abnormalcondition.

I claim:

1. A fluid actuated alarm system, comprising: a pressure source, aplurality of sensing devices, each capable of creating a pressure changeupon the occurrence of an abnormal condition; a plurality of visualunits, one for each of said sensing devices; an audible alarm; a valvefor controlling said audible alarm; a pressure connection from saidpressure source to each of said sensing devices; a pressure connectionbetween each sensing device and its corresponding visual unit; apressure header operatively connected with said valve for effecting theoperation thereof; a plurality of conduits, one leading from said headerinto each of said units; each of said units including a visual alarmindicator, means responsive to pressure changes caused by the sensingdevice connected therewith to actuate its visual indicator to an alarmposition and contemporaneously effect a pressure change in thecorresponding conduit leading thereto for opening said valve andsounding said audible alarm, means to actuate its visual indicator to amodified alarm position and contemporaneously restore normal pressure inthe conduit leading thereto for closing said valve and silencing saidaudible alarm; and means to return its visual indicator to normalposition.

2. A fluid actuated alarm unit, comprising: a bellows responsive to apressure change upon the occurrence of an abnormal condition; a latchoperated by said bellows, a visual alarm indicator normally held incocked position by said latch; biasing means acting on said indicator,whereby response by said bellows to a pressure change trips said latchto allow the biasing means to move said indicator to alarm position; asecond latch whereby said indicator is retained in alarm position; meansto trip said second latch and permit said biasing means to move saidindicator to modified alarm position; and means to return the indicatorto cocked position.

3. A fluid operated alarm unit for operative connection by a pressureline to a sensing device and pressure source, comprising: a bellowsresponsive to first pressure changes in said line caused by said sensingdevice; a rotatable shaft; a visual indicator mounted on said shaft andnormally held in cocked position by said bellows; biasing means on saidshaft to rotate said indicator to alarm position; an audible alarm; ableeder line operatively connecting said audible alarm with said unit; alever engageable with said shaft to stop the rotation thereof; a bleedervalve on the bleeder line, said bleeder valve being carried by saidlever; means connecting said audible alarm to said pressure source; anaudible alarm control valve in said pressure source connecting means;and means responsive to pressure changes in said bleeder line andconnected to said audible alarm control valve, whereby response by saidbellows to said first pressure changes trips said indicator for rotationthereof to alarm position, and engagement by said lever with said shaftcontemporaneously ends said rotation and opens said bleeder valve toallow said pressure responsive means to open said audible alarm controlvalve, thereby sounding said audible alarm.

4. Apparatus as described in claim 3 and additionally including means totrip said lever and permit said biasing means to rotate said indicatorto alarm-acknowledged position, and means anchored to said bleeder valveand operative upon the tripping of said lever to close said bleedervalve, thereby closing said audible alarm control valve and silencingsaid audible alarm.

5. Apparatus as described in claim 4 and additionally comprisingapparatus to reset said indicator, comprising a cable anchored to andwound about said shaft, and means to pullsaid cable and counteract saidshaft biasing means, thereby returning said indicator to normal cockedposition.

6. A fluid operated alarm system for the protection of a plurality offield stations, comprising a plurality of sensing devices, one for eachstation, and each device being capable of creating a pressure changeupon the occurrence of an abnormal condition; a pressure source; aplurality of alarm units, each operatively connected to at least one ofsaid devices; an audible alarm responsive to said pressure change andoperatively associated with said alarm units; a bellows in each unit,responsive to said pressure change caused by the respective deviceconnected thereto; a rotatable shaft in each unit; biasing meansanchored on said shaft; a visual indicator mounted onsaid shaft;retaining means in each unit, connected to said bellows, to engage saidshaft and hold said indicator in cocked position, and operable by saidbellows to release said shaft upon said pressure change, permitting saidindicator toassume an alarm position; second retaining means to holdsaid indicator in alarm position; a pressure header; individual bleedertake-offs from said header to each of said units for the actuation ofsaid audible alarm; a bleeder stop valve carried by said secondretaining means to normally close the bleeder associated. therewith,said bleeder valve being opened upon the release of said shaft by saidretaining means; pressure responsive means connected to said header; anaudible alarm control valve, operable by said pressure responsive means,whereby actuation of said bleeder valve to open said bleeder causes saidpressure responsive means to open said audible alarm valve; means totrip said second retaining means and permit said shaft to rotate saidindicator to a modified alarm position; and means to close said bleedervalve and silence said audible alarm.

7. Apparatus as described in claim 6 and additionally comprisingapparatus to reset said indicator, including a cable anchored to andwound about said shaft, and means to pull said cable and counteract saidshaft biasing means, thereby returning the indicator to cocked position.

8. In a fluid actuated alarm unit having a pressure responsive bellowsand an alarm indicator, the combination of an alarm indicator andactuating assembly, including a rotatable shaft to carry said indicator;stop means on said shaft; biasing means anchored to said shaft andoperating thereon; a finger normally engaging said stop means to retainsaid indicator in a cocked position, said finger being connected to saidbellows and tripable thereby to displace said indicator to announce afirst condition, comprising an alarm; a second finger adapted to engagesaid stop and retain said indicator in alarm position; means topivotally support said fingers; means to trip said second finger topermit said indicator to rotate and announce a second condition,comprising an acknow ledged alarm; a cable anchored to and adapted towind about said shaft as said indicator announces said first and secondconditions; and means to pull said cable and counteract said biasingmeans to move said indicator to cocked position, comprising normalcondition.

9. Apparatus as described in claim 8 and additionally comprising anaudible alarm control valve including a third finger carried by saidsecond finger, said third finger being normally engaged with an openbleeder line and adapted to be movable therefrom to actuate an audiblealarm; and means to close said bleeder and silence said audible alarm.

References Cited in the file of this patent UNITED STATES PATENTS456,824 Hunt July 28, 1891

